Typically, tubular grafts are stitched by hand to metallic stent structures and this process can take a long time. Other problems with the process include difficulties in controlling and assuring the quality and the cost of the final product.
An alternative solution has been described in WO 99/37242 (in the name of the present applicant) in which computerized embroidery is used to manufacture a flat-form device which is subsequently rolled into a tube. This approach solves many of the issues associated with hand manufacturing but results in a seam and prevent some continuous structures from being designed.
GB 2165559 (University College London) discloses a sewing machine for forming stitches in a substrate, for example body tissue, during surgery. The sewing machine employs suction to pull a folded section of the substrate into the machine so that it is disposed between a needle and a hook. The needle can then be used to feed thread through the folded section of substrate to emerge the other side, and to engage the thread on the hook. This action is repeated with the sewing machine being moved along the substrate, thereby forming stitches in the substrate. This sewing machine could not be employed to stitch thread to the wall of a tubular graft, because the graft would not be sufficiently compliant to enable a folded section of graft to be sucked into the machine.
U.S. Pat. No. 4,502,159 (Shiley Incorporated) discloses a method for forming a tubular prosthesis by rolling pericardial tissue into a tube and stitching along the tube to form a longitudinal seam. However, the stitches are formed conventionally by passing a thread from one side of the seam to the other on the outside of the tube.
U.S. Pat. No. 4,241,681 (Porter) discloses a sewing machine for sewing a series of spaced reinforcing rings on a long flexible tube of fireproof fabric. The machine comprises a long tubular support over which the work piece is pulled like a sleeve on an arm. A fixed stitching mechanism is provided for forming chain stitch in the work piece, and a puller mechanism advances the work piece over the support as the stitches are formed therein.
U.S. Pat. No. 4,414,908 (Janome Sewing Machine Co., Limited) discloses a suturing machine for suturing incised parts of a patient. The machine comprises a needle holder (effectively a pair of pliers) and a shuttle holder which is slideably mounted on the needle holder. This means that movement of the needle independently of the shuttle is not possible for all degrees of freedom. In an alternative embodiment, the needle is rotatable circumferentially around the shuttle. The apparatus is not suitable for sewing a tubular implant.